The Chargers were quick to add Keiser in mid-May, days after his release by the Panthers and a serious knee injury to San Diego pass rusher Melvin Ingram. Keiser is having a solid training camp, albeit one interrupted by a hamstring strain for a few days last week, and is competing to provide depth at a position of need.

"I feel the best I have (in my NFL career)," Keiser said. "Everything is flowing right now."

The 24-year-old was a defensive end prior to his 2010 season at Stanford. The Cardinal hired current 49ers coordinator Vic Fangio, implementing a 3-4 scheme that moved Keiser to outside linebacker. He then worked mostly at defensive end in Carolina.

Here in San Diego, he finds a multiple 3-4 defense in which he'll be serviced from a two-point or three-point stance, varying play-to-play on coordinator John Pagano's front. And there is opportunity to compete for a roster spot out of camp, as Jarret Johnson, Dwight Freeney and Larry English are the only other outside linebackers on the roster who have played an NFL down entering Thursday's preseason opener against Seattle.

Keiser, listed at 6-foot-4 and 260 pounds, took 311 defensive snaps in Carolina.

He notched 16 tackles, 4.5 sacks with an interception and pass defensed.

"It seems like everything in my career over the past four or five years has prepared me to have success in this situation in San Diego as far as the defense and my role and position go," Keiser said. "I look back at my Stanford time, and I was missing a step. There was too much thinking. I went to the NFL, played a lot of defensive end, really developed my skills there dramatically and started dipping back to outside linebacker.

"Now I'm here, understanding the system, and everything is just react-and-go instead of, 'All right, this is what I have to do. Ah, what about this?' Now it's just run around as fast as you can and play and do the right thing."

Related

No cavalry is coming for the current depth in the Chargers' front seven.

Freeney on May 21 was the last signing there. While the team is keeping tabs on available veterans, a newly acquired veteran is not necessarily seen as an upgrade over some of the younger, developing players in place.

That includes Keiser, who has worked to become what he calls "extremely well-rounded as an outside linebacker."

"I've had the four years to develop all those skills," Keiser said. "Now, it's fun to actually put them into use."